Multi-adjustable drill guide for dental prosthesis

ABSTRACT

In one aspect, a group of prefabricated components to form a drill guide system for drilling a properly spaced and oriented implant hole adjacent to another implant hole or adjacent to a fully-installed implant is disclosed. In another aspect, improved procedures for drilling a dental implant hole adjacent to another implant hole are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to dental prosthetics, and moreparticularly, to intra-oral framework systems and components forimplant-supported prosthetic restorations. The invention further relatesto methods and apparatus for properly positioning and guiding a drillduring dental implant surgery.

2. Description of the Related Art

One of the fastest growing specialties in dentistry is prosthodontics,which is the replacement of missing natural teeth with prostheticrestorations, such as a single tooth, a bridge of several prostheticteeth, or a denture comprising an arc of prosthetic teeth for anedentulous or partially edentulous patient. The prosthetic restorationsare shaped and colored to appear like natural teeth, and are typicallysupported on dental implants that are surgically secured within thepatient's jawbone. Various implant designs are available, such asblades, screws and cylinders, and the implants are generally made oftitanium or high titanium alloy.

The conventional surgical procedure for installing one,implant-supported, prosthetic tooth includes drilling a properlypositioned hole in the jawbone of the patient, inserting the implant inthe hole, and attaching the prosthetic tooth to the implant. Incircumstances where two or more implants are installed to support aprosthetic bridge, each implant hole must be angled properly and locatedthe correct distance from adjacent implants and natural teeth to achieveproper alignment and appearance for the prosthetic restoration. Properimplant positioning is also extremely important to ensure that theimplant is anchored within sufficient bone structure in the patient'sjawbone. Typically, to install an entire upper or lower denture, atleast four implant holes are drilled into the upper or lower jawbone.

The most common method for locating a dental implant hole is to visuallysurvey the area and drill the hole in a freehand manner. However, thismethod can readily result in imperfect bores due to space limitationsassociated with working inside a patient's mouth. Thus, dental surgeonshave encountered difficulty forming implant holes with a sufficientdegree of parallelism and proper positioning. A variety of problems canresult from flawed or imperfect implant holes, such as uneven forcedistribution, insufficient bone growth around the implant, secondaryinfections, and ultimately, implant failure. Therefore, various types ofsurgical stents and positioning guide systems have been developed to aidthe dental surgeon.

A traditional surgical stent is a custom-built template for properlyspacing dental implants and for guiding the drill as the implant holesare formed. One exemplary method for making and using a surgical guidestent is described in U.S. Pat. No. 5,556,278 to Meitner, herebyincorporated herein by reference. First, a cast impression is made ofthe patient's mandible or maxilla jawbone (arch) that includes anedentulous space where one or more implant-supported prosthetic teethwill be installed. A diagnostic tooth set-up formed of wax or otherknown material is made to fit within the edentulous space of the castarch. Next, the dental surgeon drills a hole through each diagnostictooth set-up and into the base of the cast arch. The hole corresponds tothe location and orientation of the implant hole in the patient's realarch. Once the hole is drilled in the cast arch, the tooth set-up isremoved, a guide post is inserted into each hole, and a guide sleeve isslid over the projecting end of the guide post. A resinous, moldablematerial is applied on the cast arch around the guide sleeves and curedto form a template. The template with the guide sleeves embedded thereinis then removed from the cast arch. When the template is ready for use,the dental surgeon inserts it into the patient's mouth, and the guidesleeves can be radiographically visualized to confirm that they are inthe optimum position and orientation before implant holes are drilledtherethrough.

Thus, such traditional surgical stents aid the dental surgeon inproperly positioning the implant holes, and also guide the drill as theimplant holes are being formed. However, because each surgical stent iscustom-built, these devices are only useful for a single patient, theyare costly to fabricate, and they require a number of intermediaryoffice and laboratory steps to take an impression of the patient's archand create a cast model from which the surgical stent is formed.

Therefore, to reduce costs and the number of steps associated withfabricating a traditional surgical stent, various forms of prefabricatedsurgical stents have been developed. One exemplary prefabricatedsurgical stent is disclosed in U.S. Pat. No. 5,775,900 to Ginsberg etal., hereby incorporated herein by reference, which describes a clear,thermoplastic acrylic resin stent to facilitate visualization of theunderlying supporting tissues. A kit is provided to the dental surgeoncomprising prefabricated stents of mandibular and/or maxillary arches insmall, medium, and large base sizes based on anatomical averages for thepopulation with various tooth arrangements on each base size. For anyparticular patient, a stent of the appropriate base size is selected andplaced in water of 120°-160° F. for approximately 2 minutes, allowingthe resin to become moldable. The inner surface of the stent is thenmolded in the mouth of the patient or on a cast model of the patient'sarch to closely approximate the edentulous ridge. Simultaneously, theouter surface of the stent is adjusted to position the prosthetic teeth.Once formed and subsequently cooled, the stent becomes stable and can beplaced in the patient's mouth at the time of implant surgery for properalignment of the implants. Thus prefabricated stents provide someadvantages over traditional surgical stents. However, each prefabricatedstent is only useful for a single patient.

In addition to surgical stents, prefabricated drill guide systems havebeen developed. One exemplary drill guide system is disclosed in U.S.Pat. No. 5,636,986 to Pezeshkian, hereby incorporated herein byreference. Pezeshkian describes prefabricated drill guide fixturescomprising interconnected housings configured in the shape of teeth withvertically disposed drill bushings passing therethrough. The drill guidefixtures are provided in different configurations depending on thenumber of prosthetic teeth that will be installed. For example, a drillguide fixture may comprise three housings fixed together in a size andconfiguration to resemble three adjacent prosthetic teeth that will beinstalled as a bridge. A pin is used to position the fixture in aninitially drilled hole, and the fixture is rotated about the axis of thepin until the tooth-shaped housings are properly aligned. The dentalsurgeon then drills through the drill bushings in each housing to formthe implant holes. The drill bushings guide the drill and reduce thelikelihood of slippage or breakage of the drill bit during drilling.Although the drill guide fixtures are prefabricated and maytheoretically be used more than once, dental restorations come in agreat variety of configurations. Therefore, the dental surgeon wouldlikely be required to purchase a separate drill guide fixture for eachpatient to provide the configuration that matches the patient'srestoration requirements.

Another exemplary drill guide system is disclosed in U.S. Pat. No.5,915,962 to Rosenlicht, hereby incorporated herein by reference.Rosenlicht describes a kit comprising a plurality of tooth emulationsthat differ in size and shape to replicate cuspids, bicuspids, molars,etc. Each tooth emulation includes a pilot guide hole extending along anaxis of rotation. The tooth emulations are connected together in anarticulated manner for relative movement and relative axial orientationto each other. The dental surgeon connects together a plurality of toothemulations to form an articulatable model approximating the size andshape of the patient's natural teeth. The model is positioned on thepatient's edentulous site, or a cast model thereof, and adjusted asnecessary. Then the model is luted or otherwise rigidified to form arigid guide for drilling implant holes into the patient's jawbonethrough the pilot guide hole in each emulation. Thus, this drill guidesystem includes prefabricated tooth emulations that are intended toenable the dental surgeon to build a model that matches the patient'srestoration configuration. However, each articulatable model is onlyuseful for one patient.

An alternate type of guide is a drill positioning guide. One exemplarytype of drill positioning guide is the Branemark System offered byNobelpharma AB. This system includes stainless steel, L-shaped guides,each comprising a vertical pin portion and a horizontal positioningportion. For each guide, the pin has a particular diameter and thepositioning portion has a particular lateral length. Once the firstimplant hole is drilled, the pin is placed inside the hole such that thepositioning portion extends horizontally over the gumline to locate thenext implant hole. The drill bit is aligned against the end of thepositioning portion opposite the pin to drill the adjacent implant hole.Therefore, the lateral length of the positioning portion determines thecenterline to centerline distance between adjacent implants to ensureadequate spacing between implants. Further, the height of thepositioning portion provides a guide for drilling the depth of theimplant hole. In particular, the positioning portion is 8 mm high, andmay include notches to indicate each 2 mm increment. The dental surgeoncan align depth indicators on the drill bit with either the full heightof the positioning portion or the notches on the positioning portion todrill implant holes of approximately equal depth.

Accordingly, the L-shaped-prefabricated positioning pins facilitatespacing between implants and enable the drilling of implant holes havingapproximately equal depth. These positioning guides may be used morethan once for any patient with any restoration configuration. However,these pins do not guide the drill bit to ensure that it remains orientedat the proper angle to drill implant holes having a sufficient degree ofparallelism. Therefore, it would be desirable to provide a drill guidesystem comprising simple, prefabricated components that may be used morethan once, for any restoration configuration, that enable preciseimplant spacing, and also ensure that the implant holes are drilled atthe proper angle and orientation.

Employing widely used conventional techniques, once the implants arepositioned, they perform no function for one to six months to allow timefor the implants to osseointegrate into the patient's jawbone. Duringthis time, the patient wears a temporary, removable denture. Once theosseointegration period is complete, the next step in providing apermanent, multi-unit restoration is to create a framework that istypically custom-fabricated in a laboratory for the individual patientfrom gold alloy or titanium components. The framework interconnects andjoins together the implants, provides a foundation for the prostheticrestoration, and provides an attachment structure for connecting theprosthetic bridge or denture to the multiple implants. Thus, theframework is a permanent structure disposed between the implants and thedental restoration.

The process for creating a custom-fabricated framework is similar to theprocess for creating a traditional surgical stent. First, a castimpression of the patient's mandible or maxilla jawbone (arch) is takenin the dentist's office, from which a model of the patient's arch ismade to indicate the locations of the implants. Using the model, theentire framework is fabricated in a laboratory to precisely fit onto theimplants. The prefabricated framework is then transferred to the dentalsurgeon for positioning onto the actual implants. Although formed usingthe model, the prefabricated framework may not precisely fit onto theimplants, in which case the framework must be adjusted. The adjustmentmay require that a bar be cut and re-soldered or re-cast, which oftenmust be performed in a laboratory that is located elsewhere. If a minorchange is required, the dental surgeon can adjust the framework in theoffice, but these modifications are typically finalized in theoff-premises laboratory. This fitting and adjustment process may go backand forth between the laboratory and the surgeon's office a number oftimes, thereby increasing the cost, time, and inconvenience to thepatient.

Another type of framework system is the laser-welded titanium framework,which does not require laboratory involvement and may be installed as anintegral part of the implant surgery to immobilize the implants. Thelaser-welded framework system allows a dental surgeon to custom buildthe titanium framework right into the patient's mouth by weldingtogether titanium components using an intra-oral welding machine. Sincethe framework is built onto the implants in the patient's mouth, a goodfit can be ensured. However, the skill required to weld intra-orallylimits the widespread application of this type of framework system.Accordingly, it would be desirable to provide a framework system thatcan be constructed directly onto the actual implants without requiringspecial skills, such as intra-oral welding.

Audax Dental AG of Basel, Switzerland offers the Connect Bar Systemcomprising a variety of components designed to be positioned to form aframework system in the dentist's office without intra-oral welding.Specifically, the Connect Bar System comprises a Housing Unit, a BarUnit, and a Bar Sleeve. The Housing Unit includes a bore for receiving afixation screw, a double-hex (12-sided) recess formed in the base forreceiving a hexagonal extension from a non-rotating abutment, and one ortwo sockets formed into the sides, each socket for receiving a ball headof a Bar Unit. The Bar Unit comprises a straight portion and a ball headformed on one end that is designed to fit into the socket of the HousingUnit. The Bar Sleeve comprises a sleeve designed to fit over thestraight portions of two adjacent Bar Units when their straight portionsare aligned, end-to-end.

To assemble the Connect Bar System, non-rotational abutments withhexagonal upper extensions are first fit onto the implants. A HousingUnit is then disposed on top of each abutment so that the double-hexrecess of the Housing Unit receives the hexagonal upper extension of theabutment, thereby enabling the Housing Unit to be adjusted to one oftwelve rotational positions with respect to the implant. A Bar Unit isconnected to each Housing Unit by inserting the ball head portion into asocket of the Housing Unit, thereby allowing full rotational movement ofthe Bar Unit with respect to the Housing Unit. Prior to installation,the Bar Units are cut to the appropriate length as perceived by thedental surgeon. To join adjacent Bar Units and complete a bar assemblythat spans between Housing Units, the Bar Sleeve is fit over the ends ofadjacent Bar Units.

Thus, the Connect Bar System offers the advantages of providing aframework system consisting of components that may be assembled togetherand installed directly into the patient's mouth without requiringintra-oral welding. However, the dental surgeon is required to preciselycut the Bar Units to the proper length, which adds to the time requiredto perform the procedure. Also, three components, namely two Bar Unitsand a Bar Sleeve, must be interrelated and assembled to form a singlebar assembly to span between two Housing Units, thereby adding to thecost and the number of components required for the framework system.Further, the Housing Unit does not connect directly to the implant butinstead connects to an intermediary non-rotational abutment, therebyadding another component to the overall prosthetic system. Additionally,the Housing Unit is restricted to one of twelve distinct rotationalpositions (30° apart) with respect to the implant, rather than havingfull rotational freedom of movement. Accordingly, it would be desirableto provide a simplified framework system of prefabricated componentsthat did not require adjustment by the dental surgeon, that had fullrotational freedom of movement with respect to the implant to maximizeadjustability during installation, and that enabled direct connection tothe implants to reduce the total number of components in the finalrestoration.

The present invention overcomes various of the deficiencies of the priorart.

BRIEF SUMMARY OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention feature a system ofcomponents that may be configured to form a framework system forimplant-supported, permanent dental restorations, and a method ofconstructing a dental framework system directly onto implants in thepatient's mouth. Certain preferred embodiments feature a system ofcomponents that may be configured to form a drill guide system, and amethod of drilling dental implant holes that are properly spaced andaligned.

In one preferred embodiment, the system comprises modular collars andconnective stem members for forming a framework system. The modularcollars preferably include a bore for receiving a fixation screw forconnection to an implant and preferably two side sockets that mayinclude bushings for receiving end portions of the connective stemmembers. The modular collars optionally include a top recess forreceiving an attachment portion of the prosthetic restoration. Themodular collars may be one-piece or two-piece components, and may beprovided in a variety of shapes. The connective members preferablyinclude a bar portion or an elbow portion with enlarged portions on eachend that are preferably spherical. The modular collars and connectivemembers are preferably separate components that interconnect to form asupporting framework for a dental prosthesis. In one respect, thecollars serve as connective nodes for connection to other such nodes viathe connective stems. Alternatively, a one-piece span member comprisinga bar portion and collar end portions on each end formed into a unitizedmember may be provided for joining two adjacent implants to support abridge. These components permit a dental surgeon to fabricate andinstall the appropriate supportive framework in the same surgicalsetting in which the implants are surgically implanted, and to createthe framework from prefabricated, premeasured components so as toprovide a properly fitting and aesthetically pleasing dental restorationwith reduced time, cost, and complexity.

In another preferred embodiment, the system comprises a positioningassembly, a connective member, and a drill sleeve for forming a drillguide system. The positioning assembly preferably comprises apositioning sleeve and paralleling pin. The positioning sleeve includesa bore for receiving the paralleling pin and a channel with a narrowedentrance for receiving one end portion of a connective member.Alternatively, the positioning assembly comprises an implant with amodular collar attached thereto. The drill sleeve preferably includes abore for receiving a drill bit and a channel for receiving another endportion of the connective member that extends between the positioningsleeve or the implant with the modular collar connected thereto and thedrill sleeve. The drill guide systems permit the dental surgeon, withgreat precision, to drill holes and install implants in the optimumposition and with the appropriate orientation, such as parallel to apreviously installed implant.

Thus, the preferred embodiments of the present invention comprise acombination of features and advantages that overcome various problems ofprior apparatus and methods. The various characteristics describedabove, as well as other features, will be readily apparent to thoseskilled in the art upon reading the following detailed description ofthe preferred embodiments of the invention, and by referring to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of the preferred embodiments of thepresent invention, reference will now be made to the accompanyingdrawings, where like components have like reference numerals andwherein:

FIG. 1 is an isometric side and top view of one embodiment of aprefabricated modular collar having a rectangular shape;

FIG. 2 is an isometric side and top view of another embodiment of apre-fabricated modular collar having an angled shape;

FIG. 3 is an isometric view of three representative connective stems ofvarying lengths;

FIG. 4 is an isometric view of an exemplary connective elbow;

FIG. 5 is an isometric view, partially in cross-section, of anotherembodiment of a pre-fabricated collar connected to an implant via afixation screw, the collar being formed of two sections;

FIG. 6 is an isometric side and bottom view of a one-piece span member;

FIG. 7 is a cross-sectional side view of the span member of FIG. 6;

FIG. 8 is a cross-sectional side view of one end of the span member ofFIG. 6 connected to an implant disposed at an angle;

FIG. 9 is an isometric top and side view of one embodiment of aninterface conversion piece that connects with a two-stage implant toextend the implant above the gumline;

FIG. 10 is an isometric top and side view of another embodiment of aninterface conversion piece;

FIG. 11 is an isometric side view, partially in cross-section, of anexemplary two-stage implant that connects with the interface conversionpiece of FIG. 9;

FIG. 12 is an isometric side view, partially in cross-section, ofanother exemplary two-stage implant that connects with the interfaceconversion piece of FIG. 10;

FIG. 13 is an isometric side view of one embodiment of interconnectedcomponents forming a preferred drill guide system;

FIG. 14 is an isometric side view, partially in cross-section, ofanother embodiment of interconnected components forming anotherpreferred drill guide system;

FIG. 15 is an isometric view of one embodiment of an assembled frameworksystem connected to implants for supporting a complete lower prostheticarch;

FIG. 16 is a cross-sectional side view of the pre-fabricated modularcollar of FIG. 1;

FIG. 17 is a cross-sectional side view of the two interconnectedsections forming the pre-fabricated collar of FIG. 5;

FIG. 18 is a top view of the drill guide system shown in FIG. 13, withthe paralleling pin and drill not shown for clarity;

FIG. 19 is a cross-sectional side view of the pre-fabricated modularcollar of FIG. 1 with rounded bushings disposed within each side socketand a connective stem connected thereto; and

FIG. 20 is a cross-sectional side view of the prefabricated modularcollar of FIG. 1 with cylindrical bushings disposed within each sidesocket and a connective stem connected thereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one aspect, the preferred embodiments of the present inventioncomprise a plurality of components that may be assembled to form adental framework for supporting and attaching a permanent,implant-supported, prosthetic restoration. Titanium is the preferredmaterial for the framework components. However, the components couldalso be formed of gold or any other material that is strong andcompatible with living tissue.

Referring to FIGS. 1-4, preferred embodiments of the frameworkcomponents preferably comprise modular collars of variousconfigurations, such as the collar 100 of FIG. 1, which may berectangular, for example, and the angled collar 150 of FIG. 2. Preferredembodiments of the framework components preferably further compriseconnective members of various shapes and sizes, such as the connectivestems 200 of FIG. 3, and the connective elbow 250 of FIG. 4.

FIG. 1 and FIG. 2 depict preferred configurations of modular collars100, 150, respectively, each comprising a preferably titanium body 102,152 with a bore 105, 155 extending axially therethrough for receiving afixation screw, an optional top recess 110, 160 for receiving anattachment portion of a prosthetic restoration, preferably two sidesockets 115, 120 and 165, 170 for joining with connective members, and alower extension 112, 162 designed to engage the top of the implant.Rather than lower extensions 112, 162, the collars 100, 150 mayalternatively include lower recesses designed to receive an extensionfrom the top of an alternative implant.

In more detail, FIG. 16 depicts a cross-sectional side view of collar100, showing side sockets 115, 120 having a preferably cylindricalcross-section. As understood with reference to FIGS. 1 and 16, sockets115, 120 of collar 100 are coaxially aligned. By contrast, and referringmomentarily to FIGS. 2 and 15, sockets 165, 170 of angled collars 150are oriented such that they lie in the same plane but are skewed withrespect to one another to intersect within bore 160 at a predeterminedangle, such as at an angle of between 100 and 170 degrees. In onepreferred embodiment, the angle of intersection of the socket axis forcollar 150 is 135 degrees.

As shown in FIG. 3, the preferably titanium connective stems 200 areelongate members that each preferably include a bar portion 210 of aparticular length having two enlarged end portions 205, 215 that arepreferably spherically shaped and adapted to fit within the side sockets115, 120 and 165, 170 of the collars 100, 150, for example. FIG. 4depicts an alternative connective elbow 250 for placement at the ends ofthe framework comprising an elbow portion 260, an enlarged end portion255 that is preferably spherically shaped for connecting to a collar100, 150, and a preferably spherically shaped rounded attachment portion265 for connecting to the prosthetic restoration. The length anddiameter of bar portions 210 of stems 200 and portion 260 of elbowconnector 250 may be any suitable dimension. Certain preferred lengthsfor connective stems 200 are approximately 8 millimeters (mm), 10 mm and12 mm measured end-to-end and, having such lengths, are approximately 2um in diameter measured across the bar portion 210. The spherical radiusof end portions 205, 215 may be, for example, approximately 1 mm.

FIG. 15 provides an isometric view of one exemplary, fully-assembledframework system 175 comprising collars 100, 150, connective stems 200,and connective elbows 250 for supporting and attaching a full prostheticlower arch. The modular collars 100, 150 connect via fixation screws 400to the implants 700. Further, the modular collars 100, 150 connect toone another via connective stems 200 such that the bar portions 210 ofthe connective stems 200 span the space therebetween. In preferredembodiments, a bushing is disposed within each of the sockets 115, 120and 165, 170 of the one-piece collars 100, 150 to receive the endportions 205, 215 of the connective stems 200, thereby providing afriction fit between the connective stems 200 and the collars 100, 150.In more detail, FIG. 19 depicts a cross-sectional side view of anexemplary one-piece collar 100 with a bushing 750 disposed in each ofthe side sockets 115, 120, the bushing 750 having a spherical recess755. The bushings 750 are preferably press-fit into the side sockets115, 120, and the end portions 205, 215 of the connective stems 200preferably snap tightly into the spherical recesses 755. Similarly, FIG.20 depicts a cross-sectional side view of the exemplary one-piece collar100 with an alternative bushing 760 disposed in each of the side sockets115, 120, the alternative bushing 760 having a cylindrical recess 765.

Both types of bushings 750, 760 provide a friction-fit to preventangular and rotational movement of the connective stems 200 with respectto the collars 100, 150. However, the cylindrical recess 765 of thealternative bushing 760 is preferably dimensioned to enable a lengthadjustment of the connective stems 200 by approximately 1 mm, forexample. Referring to FIG. 15, if a connective stem 200 a of 7 mmend-to-end length is required to connect between collar 100 a and collar150 a, then a connective stem 200 a of 8 mm may be utilized if at leastone of the sockets 105, 170 includes an alternative bushing 760 with acylindrical recess 765 that enables a 1 mm lengthwise adjustment.Further, a connective stem 200 a of 9 mm may be utilized if both of thesockets 105, 170 include a bushing 760 that enables a 1 mm lengthwiseadjustment.

As understood with reference to FIG. 15, collars 100, 150 serve asconnective nodes that tie together other components of the frameworksystem 175. For example, angled collar 150 a serves as a connective nodeby interconnecting collars 100 a and 150 b via stems 200 a, 200 b. As afurther example, collar 100 b serves as a connective node byinterconnecting collar 150 b and elbow 250 b via its connection withstem 200 c. As described more fully below, framework 175, once assembledand installed on implants 700, creates a supporting system for a dentalprosthesis, where the system is constructed from prefabricated andpresized components to satisfy the unique requirements of the particularpatient. The non-angled modular collars 100 are preferably connected toimplants 700 toward the back of the arch, while the angled collars 150are preferably connected to implants in the front of the arch. Further,connective elbows 250 are preferably provided at the very back of thearch on each side. In order to depict how the implants 700 and collars100, 150 fit together, the collars 100, 150 are shown displaced from theimplants 700. However, when the framework system 175 is installed, thefixation screws 400 will be fully threaded into the implants 700,thereby causing the lower portions 112, 162 of collars 100, 150 to fitinto the upper recesses 710 of the implants 700 such that the collars100, 150 are mounted directly atop the implants 700.

Various alternate embodiments of framework components may be provided.FIGS. 5 and 17 depict an alternate two-piece, split collar 130, whichmay be utilized instead of the one-piece modular collars 100, 150. FIG.5 is an isometric view, partially in cross-section, of the two-piececollar 130 connected to an implant 300 via a fixation screw 400, andFIG. 17 depicts the two-piece collar 130 in a side, cross-sectionalview. The two-piece collar 130 comprises an upper section 135 and alower section 140 that preferably interconnect via a tab 136 extendingdownwardly from the upper section 135 into a tab 142 extending upwardlyfrom the lower section 140, thereby creating an interference fit. Thetwo-piece collar 130 includes an axial bore 132, that preferablyincludes internal threads 139, extending through both sections 135, 140for receiving the fixation screw 400, and preferably two side sockets134, 138 formed when the upper and lower sections 135, 140 areinter-locked together. The internal threads 139 in the axial bore 132are provided to enable disengagement of the two sections 135, 140 viathe jackscrew method. Before the collar 130 is connected to the implant300, the upper and lower sections 135, 140 are slightly separated asshown in FIG. 17, thereby forming gaps 133, 137 in the side sockets 134,138. This separation provides adequate space for the end portions 205,215 of a connective stem 200 to engage the side sockets 134, 138 whilethe position of the connective stem 200 is being adjusted.

Once the angle and orientation of the connective stem 200 is set, theupper and lower sections 135, 140 of the two-piece collar 130 arepress-fit together around an end portion 205, 215 of the connective stem200 by tightening the fixation screw 400 through the collar 130. Asshown in FIG. 5, the two-piece collar 130 connects to an implant 300having a threaded axial bore 320 for receiving the fixation screw 400.The screw 400 is tightened to a specified torque to compress the endportion 205, 215 of the connective stem 200, thereby preventing the stem200 from rotating with respect to the two-piece collar 130. The implant300 further includes external threads 310 that anchor to bone in thepatient's jaw when the implant 300 is installed.

In still another embodiment, shown in isometric view in FIG. 6 and incross-sectional side view in FIG. 7, a one-piece span member 180 may beprovided to connect between adjacent implants. The one-piece span member180 is utilized with a bridge restoration supported by only twoimplants. The span member 180 comprises a bar portion 225 and two collarends 185, 190, each having an axial bored area 187, 192. Bored areas187, 192 include inwardly tapered surfaces 191 and a central axis 193.FIG. 8 depicts one end of the span member 180 connected to an implant350 disposed at an angle relative to the central axis 193 of collar end190. The implant 350 includes external threads 360, an internal threadedbore 370 for receiving a fixation screw (not shown), and an internalhexagonal recess 380. The collar ends 185, 190 and the bar portion 225of the span member 180 are integrated into one unitized component, andthe collar ends 185, 190 are preferably sized and configured so thatportions 188 of the collar ends 185, 190 extend into the recess 380 ofthe implant 350 and enable rotational movement with respect to theimplant 350. Preferably, portions 188 of collar ends 185, 190 aregenerally spherical in shape. The axial bored areas 187, 192 are eachadapted to accept a fixation screw to secure the span member 180 to theimplant 350. The bridge restoration connects to the implant 350 bysnapping into place on the bar portion 225 of the span member 180. It ispreferred that bored areas 187, 192 have a diameter substantiallygreater than the diameter of the fixation screw used to attach spanmember 180 to implants 350 so as to be employable with implants that aredisposed at an angle relative to the axis of collar end 185, 190, asshown in FIG. 8.

Each of the preferred embodiments of the framework collars describedabove is designed to connect directly onto an implant that extends abovethe gumline. However, the dental surgeon may utilize two-stage implantscomprising a first stage that stops below the gumline and a second stagethat connects to the first stage and extends above the gumline. Thus,additional preferred embodiments of the framework components compriseinterface conversion pieces of various configurations, such as pieces500, 550 of FIG. 9 and FIG. 10, respectively. Conversion pieces 500, 550connect to the first stage of a two-stage implant and extend above thegumline such that collars 100, 150, 130 and span member 180 can connectthereto. In one embodiment, the conversion piece 500 of FIG. 9 includesa hexagonal extension 505, a threaded axial throughbore 510, and anupper recessed portion 515. In another embodiment, the conversion piece550 of FIG. 10 comprises a multi-sided recess 555 and an upper recessedportion 565.

FIG. 11 depicts the first implant stage 600 of one exemplary, prior art,two-stage implant having external threads 605, a threaded axial bore 610for receiving a fixation screw (not shown), and a hexagonal recess 620.The conversion piece 500 of FIG. 9 can be utilized in place of aconventional second stage to extend the first implant stage 600 of FIG.11 above the gumline by fitting the hexagonal extension 505 of theconversion piece 500 into the hexagonal recess 620. Then the lowerportions of the modular collars, such as, for example, the lowerportions 112, 162 of collars 100, 150 of FIGS. 1 and 2, respectively,fit into the upper recessed portion 515 of the conversion piece 500, anda fixation screw (not shown) is threaded through the collar 100 or 150,the conversion piece 500, and into the first implant stage 600. Thus,the conversion piece 500 enables the preferred embodiments of theframework components, such as collars 100, 150, to be utilized withtwo-stage implants.

FIG. 12 depicts a first implant stage 650 of another exemplary, priorart, two-stage implant having external threads 655, an internal threadedbore (not shown), and a hexagonal extension 670. The conversion piece550 of FIG. 10 is utilized to extend the first implant stage 650 abovethe gumline by fitting the hexagonal extension 670 of the first implantstage 650 into the multi-sided recess 555 of the conversion piece 550.The lower portions 112, 162 of the modular collars 100, 150 shown inFIGS. 1-2, for example, fit into the upper recessed portion 565 of theconversion piece 550, and a fixation screw (not shown) extends throughthe collar 100 or 150, the conversion piece 550, and into the firstimplant stage 650. Accordingly, interface conversion pieces, such asconversion pieces 500, 550 of FIGS. 9 and 10, respectively, would onlybe utilized with the first implant stage of two-stage implants, such asfirst implant stages 600 and 650 that stop below the gumline. Theconversion pieces, such as pieces 500 and 550, act to extend the firstimplant stages 600 and 650 above the gumline so that the frameworkcomponents can be attached thereto.

In another aspect, the preferred embodiments of the present inventioncomprise a plurality of components that may be assembled to form a drillguide system for drilling properly spaced and aligned dental implantholes for multi-unit prosthetic restorations. FIG. 13 and FIG. 14 depictthe components of two preferred embodiments, respectively, of a drillguide system connected together. The drill guide systems of FIGS. 13-14each comprise a positioning assembly 850, a connective stem 200, and adrill sleeve 950. As shown in FIGS. 13 and 18, one embodiment of thepositioning assembly 850 comprises a paralleling pin 800 and apositioning sleeve 900. The positioning sleeve 900 preferably includes athroughbore 905 for receiving the paralleling pin 800 and a channel 910for receiving the end portion 205 of the connective stem 200. The drillsleeve 950 preferably includes a throughbore 955 for receiving a drillbit 50 and a channel 960 for receiving the opposing end portion 215 ofthe connective stem 200, thereby joining the drill sleeve 950 to thepositioning sleeve 900 via bar portion 210. Channel 910 and channel 960each have a narrowed opening 912. Openings 912 are wider than thediameter of bar portion 210 of stem 200 but smaller in width than thediameter of spherical ends 205, 215. In this manner, channels 910, 960and their respective narrow entrance or opening 912, form a capture forreceiving and securing ends 205, 215 of stem 200.

To utilize the drill guide system of FIGS. 13 and 18, a first implanthole is drilled using conventional techniques, and the paralleling pin800 is then placed through the positioning sleeve 900 to extend into thefirst implant hole. A connective stem 200 with a bar portion 210 of theappropriate length to provide the desired center-to-center spacingbetween implants is then selected by the dental surgeon. The end portion205 of the connective stem 200 is slid downwardly in the channel 910 ofthe positioning sleeve 900, and the opposing end portion 215 is sliddownwardly in the channel 960 of the drill sleeve 950, thereby joiningthe two sleeves 900, 950 as ends 205, 210 are captured within channels910, 960. A drill bit 50 is then placed through the bore 955 of thedrill sleeve 950, and a second implant hole is drilled therethrough.Accordingly, the connective stem 200 locates the drill sleeve 950through which the drill bit 50 drills the second implant hole. Thelength of the drill sleeve 950 is sufficiently long to guide the drillbit 50 and prevent the drill bit 50 from drilling off angle, ensuringthat the second implant hole is drilled parallel to the first. In likemanner, all other implant holes are drilled at the proper distance andorientation, so that a framework system such as that shown in FIG. 15can be constructed.

An alternative embodiment of the positioning assembly 850 comprisesreplacing the paralleling pin 800 and positioning sleeve 900 of FIG. 13with a fully-installed first implant having a modular collar attachedthereto. FIG. 14 depicts an exemplary configuration of the alternativepositioning assembly 850 comprising the implant 300 of FIG. 5 with atwo-piece collar 130 attached thereto via a fixation screw 400. Tolocate a second implant hole with respect to the first, previouslyinstalled, implant 300, a connective stem 200 with a bar portion 210 ofthe appropriate length to provide the desired center-to-center spacingbetween implants is selected by the dental surgeon. One end portion 205of the connective stem 200 is press-fit into the side socket 138 of thecollar 130, and the opposing end portion 215 of the connective stem 200is slid downwardly in the channel 960 of the drill sleeve 950 where itis captured by narrowed opening 912, thereby joining the drill sleeve950 to the implant 300. A drill bit 50 is placed through the bore 955 ofthe drill sleeve 950, and a new implant hole is drilled therethrough.Then the drill bit 50 and drill sleeve 950 are removed to installanother implant and modular collar in the second implant hole, such asthe implant 300 and the collar 130, for example.

In yet another aspect, preferred embodiments of the present inventioncomprise an improved procedure for installing a multi-unit prostheticrestoration. In particular, one preferred embodiment of the improvedprocedure comprises a method of drilling properly spaced and parallelimplant holes, installing the implants in the drilled holes, fabricatinga dental framework system directly onto the implants in the dentalsurgeon's office, and attaching a multi-unit prosthetic restoration tothe framework, all in a single surgical setting. As used herein, thephrase “single surgical setting” when used to describe the timingassociated with performing various procedures or steps means that allsuch steps are performed during a single visit to the office of thedental professional, as contrasted with performing those steps overmultiple visits by the patient over various days, weeks or months.

In more detail, one preferred embodiment of the procedure comprisestaking an impression of the patient's edentulous ridge from which a castmodel of the patient's arch is made. Using the model and otherdiagnostic information, the dental surgeon can determine the locationand angular orientation of each implant, determine which prefabricatedframework components of the present system will be used, and fabricatethe prosthetic restoration that will be installed. On the day ofsurgery, the implant holes will be drilled as planned, preferablyutilizing the drill guide components and methods heretofore describedwith respect to FIGS. 13, 14 and 18. The implants will then beinstalled. Then the framework will be installed, preferably utilizingthe prefabricated modular collars and connective members of thepreferred embodiments of the present invention. Accordingly, theframework will be installed, component by component, in the dentist'soffice in the same surgical setting as the implants.

Referring again to FIG. 15, an isometric view is shown of one exemplaryimplant and framework system for a full prosthetic lower arch comprisingfour implants 700, with modular collars 100, 150 connected via fixationscrews 400 to the implants 700. Further, the modular collars 100, 150are connected to one another via connective stems 200 having barportions 210 that span the space therebetween. As previously disclosed,in order to best depict how the implants 700 and collars 100, 150 fittogether, the collars 100, 150 are shown displaced from the implants700. However, when the framework system is installed, the lower portions112, 162 of collars 100, 150 will fit into the upper recesses 710 of theimplants 700 to mount the collars 100, 150 directly atop the implants700, and the fixation screws 400 will be fully threaded into theimplants 700.

Once the implants 700 and framework system are installed, the prostheticdenture can be attached to the framework. Preferably, the denture wouldinclude attachment recesses for receiving the bar portions 210 of theconnective stems 200 a, 200 b, 200 c, thereby enabling the denture tosnap into place onto the framework system. Optionally, the denture mayinclude attachment extensions matching the position and size of theoptional top recesses 110, 160 of the modular collars 100, 150 toprovide an additional means for securing the denture to the frameworksystem. The denture preferably further includes two sockets at the veryback of the arch matching the position and size of the attachmentportions 265 of the connective elbows 250, thereby enabling the dentureto snap into place at this location.

This method of installing the implants, framework, and prostheticrestoration in the same surgical setting will obviously result inimmediate loading on the implant-supported denture since no delay isprovided to allow the implants to osseo-integrate into the jawbone.Conventionally, a delay of 1-6 months is provided for osse-integrationof the implants into the jawbone. However, immediate loading is nowadvocated by a number of dental surgeons and dental prosthetic companiesas a condition that is beneficial to osseo-integration. Accordingly, asimmediate loading becomes a more accepted and more widespread practice,the above-described single surgical setting procedure will be beneficialfor reducing time, cost, and inconvenience to the patient.

Another embodiment of the present invention comprises an improvedprocedure for installing a multi-unit prosthetic restoration withoutimmediate loading. The procedure for installing the implants andframework system would preferably be the same as previously described,i.e. the implants and framework system would be installed in the samesurgical setting. Following installation of the framework system, suchas that shown in FIG. 15, another impression would be made of thepatient's edentulous ridge, this time with the implants and frameworksystem installed. Another model of the patient's arch would be made fromthis impression, from which the prosthetic restoration would be built.Utilizing this procedure, the patient would wear a temporary, removabledenture while the permanent denture was being built, and the frameworkcould either remain in the patient's mouth during that period, or itcould be removed and reinstalled at the time when the permanent dentureis attached.

Accordingly, in one aspect, the preferred embodiments of the presentinvention comprise a group of inter-connecting, prefabricated,preferably titanium components of various shapes and sizes that can beassembled together to form a framework system directly onto implantsinstalled in the patient's mouth. Thus, the framework can be fabricatedon site in the dental surgeon's office in a single surgical setting sothat multiple trips back and forth to the surgeon's office and/or dentallaboratory are eliminated. Further, no intra-oral welding is required,nor adjustment of system components, such as by cutting connectivemembers to fit.

In another aspect, the preferred embodiments of the present inventioncomprise a group of inter-connecting, prefabricated components to form adrill guide system for drilling an implant hole adjacent to anotherimplant hole or adjacent to a fully-installed implant. Namely, the drillguide system previously described enables implants to be drilled at theproper distance and in a parallel relationship to adjacent implants.Further, none of the drill guide system components are custom-made, norare they destroyed during use, such that they can preferably be utilizedmore than once, for any configuration of restoration, and on anypatient.

In yet another aspect, the preferred embodiments of the presentinvention comprise improved procedures for installing permanent,implant-supported dental restorations. If the doctor believes immediateloading is preferred, then using a model of the patient's arch, theimplants can be located, the framework can be designed, and the dentureprosthesis can be pre-fabricated—all in advance. Accordingly, when thepatient arrives on the day of dental surgery, the implants can beinstalled, the framework constructed and attached to the implants, andthe denture fixed to the framework, such that the entire installation iscompleted in a single surgical setting.

Further, if the doctor does not believe that immediate loading ispreferred, the procedure of the preferred embodiments still providestime and cost-saving advantages because the framework need not becustom-built in a laboratory, but instead can be constructed andinstalled in the same surgical setting in which the implants aresurgically implanted. Then an impression of the installed implantsand/or framework can be made to form a model from which the dentalprosthesis can be built for installation after the osseo-integrationperiod.

While preferred embodiments of this invention have been shown anddescribed, modifications thereof can be made by one skilled in the artwithout departing from the spirit or teaching of this invention. Theembodiments described herein are exemplary only and are not limiting.Many variations and modifications of the system and apparatus arepossible and are within the scope of the invention. Accordingly, thescope of protection is not limited to the embodiments described herein,but is only limited by the claims that follow, the scope of which shallinclude all equivalents of the subject matter of the claims.

1. A system of prefabricated components for forming a drill guide,comprising: a positioning assembly; a connective member; and a drillsleeve.
 2. The system of claim 1 wherein said positioning assemblycomprises a paralleling pin disposed through a positioning sleeve. 3.The system of claim 1 wherein said positioning assembly comprises animplant with a collar connected thereto.
 4. The system of claim 1wherein said drill sleeve includes a receiving slot, and wherein saidconnective member includes an enlarged end portion retained within saidslot, said connective member disposed between said positioning assemblyand said drill sleeve.
 5. The system of claim 2 wherein said positioningsleeve and said drill sleeve each include an outer surface and a channelfor capturing an end of said connective member, said channel extendingfrom said outer surface into the interior of said sleeve and being morenarrow at said outer surface than at said interior so as to form acapture for said end of said connective member.
 6. A method of drillinga dental implant hole adjacent a first implant hole comprising:disposing a positioning assembly in the first implant hole; connectingthe positioning assembly to a drill sleeve; and drilling the dentalimplant hole through the drill sleeve.
 7. The method of claim 6 whereindisposing a positioning assembly in the first implant hole comprisesdisposing a paralleling pin through a positioning sleeve and into thefirst implant hole.
 8. The method of claim 6 wherein disposing apositioning assembly in the first implant hole comprises disposing animplant having a framework component connected thereto in the firstimplant hole.
 9. The method of claim 6 wherein connecting thepositioning assembly to a drill sleeve comprises disposing a bar portionbetween the positioning assembly and drill sleeve.